Sea urchins Mellita quinquiesperforata (Leske) were collected in the Colombian Caribbean and aqueous, methanolic and dicloromethane extracts were obtained and the total phenol contents were determined, yielding values of 10.97, 9.47, and 9.22 mg EAG/g, respectively. Moderate antioxidant activity against ABTS cationic radicals was documented, with IC50 values = 85.60, 76.75, and 98.19 μg/ml for the same extracts, while activity against DPPH radicals were documented as lower, with IC50 values exceeding 200 μg/ml in all cases evaluated. In the determination of ferric reduction potential, moderate values of reduction were documented, with 3.24, 3.37, and 3.42 mg EAA/g from the metanholic, dicloromethanol, and aqueous extracts, respectively. On the other hand, the lipid fraction of dicloromethanol was determined, from which 38 organic compounds, 30 fatty acids, and 8 sterols were identified, with structural variations. The results show that M. quinquiesperforata is able of to produce compounds capable of inhibiting the ABTS radical, as well as reduce Fe+3, but they are not efficient in inhibiting the DPPH radical.